kernel_optimize_test/drivers/media/IR/ir-rc5-decoder.c

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/* ir-rc5-decoder.c - handle RC-5 IR Pulse/Space protocol
*
* Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
/*
* This code only handles 14 bits RC-5 protocols. There are other variants
* that use a different number of bits. This is currently unsupported
* It considers a carrier of 36 kHz, with a total of 14 bits, where
* the first two bits are start bits, and a third one is a filing bit
*/
#include <media/ir-core.h>
static unsigned int ir_rc5_remote_gap = 888888;
#define RC5_NBITS 14
#define RC5_BIT (ir_rc5_remote_gap * 2)
#define RC5_DURATION (ir_rc5_remote_gap * RC5_NBITS)
/* Used to register rc5_decoder clients */
static LIST_HEAD(decoder_list);
static DEFINE_SPINLOCK(decoder_lock);
enum rc5_state {
STATE_INACTIVE,
STATE_MARKSPACE,
STATE_TRAILER,
};
struct rc5_code {
u8 address;
u8 command;
};
struct decoder_data {
struct list_head list;
struct ir_input_dev *ir_dev;
int enabled:1;
/* State machine control */
enum rc5_state state;
struct rc5_code rc5_code;
unsigned code, elapsed, last_bit, last_code;
};
/**
* get_decoder_data() - gets decoder data
* @input_dev: input device
*
* Returns the struct decoder_data that corresponds to a device
*/
static struct decoder_data *get_decoder_data(struct ir_input_dev *ir_dev)
{
struct decoder_data *data = NULL;
spin_lock(&decoder_lock);
list_for_each_entry(data, &decoder_list, list) {
if (data->ir_dev == ir_dev)
break;
}
spin_unlock(&decoder_lock);
return data;
}
static ssize_t store_enabled(struct device *d,
struct device_attribute *mattr,
const char *buf,
size_t len)
{
unsigned long value;
struct ir_input_dev *ir_dev = dev_get_drvdata(d);
struct decoder_data *data = get_decoder_data(ir_dev);
if (!data)
return -EINVAL;
if (strict_strtoul(buf, 10, &value) || value > 1)
return -EINVAL;
data->enabled = value;
return len;
}
static ssize_t show_enabled(struct device *d,
struct device_attribute *mattr, char *buf)
{
struct ir_input_dev *ir_dev = dev_get_drvdata(d);
struct decoder_data *data = get_decoder_data(ir_dev);
if (!data)
return -EINVAL;
if (data->enabled)
return sprintf(buf, "1\n");
else
return sprintf(buf, "0\n");
}
static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
static struct attribute *decoder_attributes[] = {
&dev_attr_enabled.attr,
NULL
};
static struct attribute_group decoder_attribute_group = {
.name = "rc5_decoder",
.attrs = decoder_attributes,
};
/**
* handle_event() - Decode one RC-5 pulse or space
* @input_dev: the struct input_dev descriptor of the device
* @ev: event array with type/duration of pulse/space
*
* This function returns -EINVAL if the pulse violates the state machine
*/
static int ir_rc5_decode(struct input_dev *input_dev,
struct ir_raw_event *ev)
{
struct decoder_data *data;
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
int is_pulse, scancode, delta, toggle;
data = get_decoder_data(ir_dev);
if (!data)
return -EINVAL;
if (!data->enabled)
return 0;
delta = DIV_ROUND_CLOSEST(ev->delta.tv_nsec, ir_rc5_remote_gap);
/* The duration time refers to the last bit time */
is_pulse = (ev->type & IR_PULSE) ? 1 : 0;
/* Very long delays are considered as start events */
if (delta > RC5_DURATION || (ev->type & IR_START_EVENT))
data->state = STATE_INACTIVE;
switch (data->state) {
case STATE_INACTIVE:
IR_dprintk(2, "currently inative. Start bit (%s) @%uus\n",
is_pulse ? "pulse" : "space",
(unsigned)(ev->delta.tv_nsec + 500) / 1000);
/* Discards the initial start space */
if (!is_pulse)
goto err;
data->code = 1;
data->last_bit = 1;
data->elapsed = 0;
memset(&data->rc5_code, 0, sizeof(data->rc5_code));
data->state = STATE_MARKSPACE;
return 0;
case STATE_MARKSPACE:
if (delta != 1)
data->last_bit = data->last_bit ? 0 : 1;
data->elapsed += delta;
if ((data->elapsed % 2) == 1)
return 0;
data->code <<= 1;
data->code |= data->last_bit;
/* Fill the 2 unused bits at the command with 0 */
if (data->elapsed / 2 == 6)
data->code <<= 2;
if (data->elapsed >= (RC5_NBITS - 1) * 2) {
scancode = data->code;
/* Check for the start bits */
if ((scancode & 0xc000) != 0xc000) {
IR_dprintk(1, "Code 0x%04x doesn't have two start bits. It is not RC-5\n", scancode);
goto err;
}
toggle = (scancode & 0x2000) ? 1 : 0;
if (scancode == data->last_code) {
IR_dprintk(1, "RC-5 repeat\n");
ir_repeat(input_dev);
} else {
data->last_code = scancode;
scancode &= 0x1fff;
IR_dprintk(1, "RC-5 scancode 0x%04x\n", scancode);
ir_keydown(input_dev, scancode, 0);
}
data->state = STATE_TRAILER;
}
return 0;
case STATE_TRAILER:
data->state = STATE_INACTIVE;
return 0;
}
err:
IR_dprintk(1, "RC-5 decoded failed at %s @ %luus\n",
is_pulse ? "pulse" : "space",
(ev->delta.tv_nsec + 500) / 1000);
data->state = STATE_INACTIVE;
return -EINVAL;
}
static int ir_rc5_register(struct input_dev *input_dev)
{
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
struct decoder_data *data;
int rc;
rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group);
if (rc < 0)
return rc;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data) {
sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
return -ENOMEM;
}
data->ir_dev = ir_dev;
data->enabled = 1;
spin_lock(&decoder_lock);
list_add_tail(&data->list, &decoder_list);
spin_unlock(&decoder_lock);
return 0;
}
static int ir_rc5_unregister(struct input_dev *input_dev)
{
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
static struct decoder_data *data;
data = get_decoder_data(ir_dev);
if (!data)
return 0;
sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
spin_lock(&decoder_lock);
list_del(&data->list);
spin_unlock(&decoder_lock);
return 0;
}
static struct ir_raw_handler rc5_handler = {
.decode = ir_rc5_decode,
.raw_register = ir_rc5_register,
.raw_unregister = ir_rc5_unregister,
};
static int __init ir_rc5_decode_init(void)
{
ir_raw_handler_register(&rc5_handler);
printk(KERN_INFO "IR RC-5 protocol handler initialized\n");
return 0;
}
static void __exit ir_rc5_decode_exit(void)
{
ir_raw_handler_unregister(&rc5_handler);
}
module_init(ir_rc5_decode_init);
module_exit(ir_rc5_decode_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
MODULE_DESCRIPTION("RC-5 IR protocol decoder");